Comparative Pharmacology
Head-to-head clinical analysis: CLOMID versus NOLVADEX.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CLOMID versus NOLVADEX.
CLOMID vs NOLVADEX
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Competitive antagonist of estrogen receptors (ER) in hypothalamus and pituitary, leading to increased gonadotropin-releasing hormone (GnRH) and subsequent LH and FSH release, stimulating ovulation.
NOLVADEX (tamoxifen citrate) is a nonsteroidal selective estrogen receptor modulator (SERM) that competitively inhibits estrogen binding to estrogen receptors in breast tissue, thereby blocking estrogen-mediated cell proliferation. It also has partial agonist activity in other tissues such as bone and endometrium.
50 mg orally once daily for 5 days, starting on day 5 of the menstrual cycle. May increase to 100 mg daily if no response.
20-40 mg orally once daily; for breast cancer, 20 mg/day. For adjuvant therapy, 20 mg/day for 5 years. For ductal carcinoma in situ, 20 mg/day for 5 years. For reduction of breast cancer incidence in high-risk women, 20 mg/day for 5 years.
None Documented
None Documented
Terminal half-life is 5–7 days for zuclomiphene (active isomer), with prolonged elimination due to enterohepatic recirculation.
Tamoxifen: 5-7 days (terminal). N-desmethyltamoxifen (active metabolite): 14 days. Steady-state achieved in 3-4 weeks.
Primarily hepatic metabolism; metabolites excreted in feces (42%) and urine (8% unchanged).
Primarily fecal (65%) as conjugates; renal excretion accounts for approximately 25% as metabolites and <0.5% as unchanged drug. Biliary elimination contributes 10%.
Category C
Category C
Selective Estrogen Receptor Modulator
Selective Estrogen Receptor Modulator